Ventilated filter tip cigarette

ABSTRACT

An improved ventilated filter cigarette utilizes uniformly porous plug wrap and tipping envelope to provide at least one uniformly porous ventilated region having a predetermined area about the filter. The area and porosity of the region or regions are correlated so as to provide a relationship which, when the limits thereof are observed, provides cigarettes with a more constant, reduced delivery of total particulate matter and gas phase constituents than heretofore obtained by ventilated filter tip cigarettes.

United States Patent 1191 Summers Dec. 9, 1975 1 VENTILATED FILTER TIPCIGARETTE [75] Inventor: Thomas Wade Summers, Fern Creek, NY.

[73] Assignee: Brown & Williamson Tobacco Corporation, Louisville, Ky.

22 Filed: Dec. 7, 1973 211 App]. No.:422,930

Related US. Application Data [63] Continuation ofSer. No. 193,124, Oct.27, 1971, Pat.

[52] US. Cl 131/10 A; 131/l0.3; 131/11; 131/12 [51] Int. Cl. ..A24B15/027; A24D 1/04; A24F 25/00 [58] Field of Search 131/10 A, 15 B, 198A, 131/10 R, 11, 90,10.3,12

[56] References Cited UNITED STATES PATENTS 2,718,889 9/1955 Claussen131/11 X 2,786,471 3/1957 Graybeal... 131/107 2,820,462 1/1958 Fleischer131/11 2,980,116 4/1961 Schur 131/15 B X 2,988,088 6/1961 Schur 131/10 A3,410,275 11/1968 Tucker... 131/10 A 3,482,579 12/1969 Davis 131/15 B X3,664,350 5/1972 Wall 131/10 A 3,707,975 1/1973 Davis 131/10 A 3,805,8004/1974 Summers [31/10 A Primary Examiner-Robbed W. Michell AssistantExaminer-V. Millin Attorney, Agent, or FirmFinnegan, Henderson, Farabowand Garrett [57] ABSTRACT An improved ventilated filter cigaretteutilizes uniformly porous plug wrap and tipping envelope to provide atleast one uniformly porous ventilated region having a predetermined areaabout the filter. The area and porosity of the region or regions arecorrelated so as to provide a relationship which, when the limitsthereof are observed, provides cigarettes with a more constant, reduceddelivery of total particulate matter and gas phase constituents thanheretofore obtained by ventilated filter tip cigarettes.

10 Claims, 7 Drawing Figures US. Patent Dec. 9, 1975 VENTILATED FILTERTIP CIGARETTE CROSS REFERENCE TO RELATED APPLICATIONS This applicationis a continuation of application Ser. No. 193,124, filed Oct. 27, 1971,now U.S. Pat. No. 3,805,800.

FIELD OF THE INVENTION The present invention relates to a ventilatedfilter tip cigarette.

BACKGROUND OF THE INVENTION In the manufacture of cigarettes withventilation, it is necessary to provide the cigarette with some means bywhich a predetermined fraction of the air drawn into the cigaretteduring puffing by-passes the burning zone. Ventilated cigarettes havebeen accepted by the general public to a limited extent. Variedventilation techniques have been employed over the past 50 years toprovide a cooler, less harsh cigarette. More recently, it has beenrecognized that ventilated cigarettes are another means by which thedeliveries of total particulate matter and gas phase constituents may bereduced.

Ventilation mechanisms may be placed into two major categories, airchanneling and perforated wrap; combinations of the two are also oftenemployed. Air channeling has frequently been embodied in cigaretteshaving corrugated mouthpieces. An example of this type of ventilation isfound early in the literature in U.S. Pat. No. 1,718,122, whichdescribes a cigarette having an internally corrugated mouthpiececircumscribing one end of the tobacco column. The outer diameter of themouthpiece being larger than the diameter of the cigarette allowed airto move along the channels provided in the corrugations and enter thesmokers mouth without first mixing with the smoke. A later U.S. Pat. No.3,490,461, similarly describes a fluted wrap about a filter overwrappedwith perforated tipping paper. Air enters through the perforations, butagain does not mix with the smoke.

For economic reasons, the preferred means of ventilating cigarettes hasheretofore been through perforated wrapping about some portion of thecigarette. Many publications and patents have described techniques ofperforating paper about the tobacco column and/or filter.

The filter perforations usually are patterned in a circumferential lineor band about the tipping paper, sometimes positioned over the junctionbetween the tobacco column and filter. Air during puffing enters theperforations and moves into the filter through the junction. U.S. Pat.No. 3,410,274 describes this feature in detail.

A visible disadvantage of perforated cigarettes, however, was theissuance of smoke through the perforations during non-puffing intervals.The most successful attempt to prevent smoke from escaping through theperforations was accomplished when plug wrap characterized by beinguniformly and highly porous became commercially available. Theperforated tipping paper was positioned over the uniformly porous plugwrap. The microscopic pores of the plug wrap significantly reducedvisible signs of smoke escaping. Registry problems between theperforations in the tipping paper and perforations previously requiredin the plug wrap were also diminished.

U.S. Pat. Nos. 2,988,088 and 3,046,994 describe uniformly porous paperwhich has met with some commercial success in being employed as filterplug wrap. This paper is provided with uniform porosity through thepaper making process. Air readily moves through the microscopic pores ofthe paper. In contrast, perforated paper is substantially non-porousexcept, of course, at the position of the macroscopic perforations. Theterms uniformly porous and uniform porosity as used hereinafter aredefined as meaning a substance which inherently has porosity distributeduniformly over its surface as distinguished from a substance givenporosity by mechanical means. It follows that substances with uniformporosity are given this characteristic in the fabrication stage unlikeperforated materials.

A problem which heretofore has continually plagued manufacturers ofventilated cigarettes using perforated wrappers, including those usinguniformly porous plug wrap, has been large variations in harshness andpressure drop between cigarettes of an identical brand and construction.Studies made on a number of present brands have shown average variationsin tar deliveries ranging from 14 to 30%. Other studies have also shownlarge variations in pressure drop. Much effort has been made to discoverthe source of the problem and to provide an economical solution. It isthe paramount object of the present invention to provide such asolution.

SUMMARY OF THE INVENTION The ventilated cigarette of the presentinvention has a filter plug wrapped with a uniformly porous wrap andoverwrapped with uniformly porous tipping envelope. The tipping envelopeand plug wrap are adhered together by an adhesive along preselectedportions of their contiguous surfaces. The remaining contiguous surfacesare adhesive-free. The adhered regions, due to the impermeability of theadhesive, become substantially non-porous in contrast to theadhesive-free regions of the plug wrap and tipping envelope whichmaintain the uniform porosity. The areas of the adhesive-free regions,ventilation regions, and the total porosity therethrough are establishedto provide a ventilation index of about 0.5 cm/sec to 20 cm/sec. Theventilation index is defined as the volume of air entering theventilation regions per second per (Federal Trade Commission) standardpuff (hereinafter called the ventilation rate) divided by the total areaof the ventilation regions.

As will be described in more detail below, the variations in totalparticulate matter yield and average pressure drop are dramaticallyreduced by employing the teachings of the present invention.

Other objects and advantages of the present invention will be apparentafter a reading of the description and appended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1(a), 1(b) and 1(c) areschematics which illustrate various prior art ventilation techniquesemploying either perforations or skinned tipping paper for ventilation:

FIG. 2 is a perspective view of a ventilated filter tip cigaretteconstructed in accordance with the present invention; and

FIGS. 3(a), 3(b) and 3(0) are schematics illustrating variations ofadhesive patterns which may be employed with ventilated filter tipcigarettes of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS wrap may either be porous orprovided with perforations which are in registry with perforations 14.An example of the latter is found in United Kingdom Patent No. 938,902assigned to the Imperial Tobacco Company. The coinciding perforationspermit ventilation.

United Kingdom Patent 989,479, also assigned to the Imperial TobaccoCompany, describes a filter tipped cigarette in which the sleeveencircling the filter stub is made from highly permeable paper which isdisposed beneath a perforated encircling band.

In FIG. 1(b) another prior art variation is illustrated in which theperforations 14 in tipping paper 15 are positioned over junction 13. Noadhesive is applied below tipping 15 in this region, thereby permittingair to be drawn through perforations 14 and into filter 12 viaunderlying junction 13.

FIG. 1(c) illustrates still another variation in which the perforationsare replaced by shaving or skinning the tipping paper above junction 13rendering the tipping paper more porous in this region. The skinnedregion is indicated by the shaded area 16. United Kingdom Patent1,039,554 describes the prior art ventilation techniques illustrated inFIGS. 1(b) and 1(c) in detail.

The underlying problem with all the above prior techniques is theinability to provide uniform pressure drop and particulate matter yieldfrom cigarette to cigarette. As is graphically depicted in the examplesbelow, tar deliveries, for example, vary as much as 30% in relativestandard deviation, for cigarettes of the prior art employing perforatedtipping. In contrast, filter tipped cigarettes described in relation toFIGS. 2 and 3, formed in accordance with the present invention, havemarkedly improved variations in pressure drop and particulate matteryields. In other words, the average measured variations of pressure dropand particulate matter yield of filter tipped cigarettes made inaccordance with the present invention are significantly smaller thanthose measured for prior art ventilated filter tipped cigarettes, andare, in fact, equivalent to normal non-ventilated filter tippedcigarettes.

The perspective view of FIG. 2 illustrates a filter tipped cigarettehaving a tobacco column 21 joined to a filter 22 at juncture 23. Filter22 is enclosed by a uniformly porous plug wrap 26. Tipping envelope 24,also uniformly porous, is disposed about wrapped filter 22 and anappropriate distance over tobacco column 21. The adhesive attachingtipping envelope 24 to plug wrap 26, thereby attaching column 21 tofilter 22, is applied to selected areas of the contiguous surfaces insuch a manner as to provide a predetermined ventilation as describedbelow.

In the discussion below the porosity of the various papers are given interms of an air flow through 143.1 mm. of paper under a head of one inchwater gauge. The measurement generally employed for the tipping papersof the prior art is a Greiner porosity index which is the number ofseconds required for the passage of 50 cubic centimeters of air througha circular sample of paper one inch in diameter, with a pressure drop ofapproximately 4.5 inches of water. Such a Greiner measurement for theporous papers employed according to the present invention would bemeaningless as the porosity is so high that all papers would have aGreiner porosity index below one. The value calculated as described,will be referred to as porosity.

To provide the proper combination of ventilated area (adhesive-freecontiguous surfaces of tipping envelope and plug wrap) and total filterpressure drop, it is necessary to use material such as paper, forexample, having a porosity of about 3 cc/sec to 40 cc/sec. By usingmaterial of the porosity above, accompanied by a ventilated region orregions having a total area of from about 0.5 cm to about 5.0 cm it hasbeen found that reduced particulate matter deliveries may be obtainedwhich, along with pressure drop, have small variations from cigarette tocigarette.

Further investigations have uncovered a critical relationship betweenthe total area of the ventilation region or regions and total filterpressure drop which, when held between certain limits, provides theunique characteristic of small variations. This relationship, called theventilation index, the volumne of air entering the ventilated region persecond per standard puff divided by the ventilated area, necessarilymust have a range of 0.5 to 20 cm/sec, and preferably between 2.0 and6.0 cm/sec.

The area of the ventilated regions have upper and lower limitations forpractical reasons. When the area becomes too small, the beneficialeffects of ventilation become undetectable, thus approaching the resultsobtained for nonventilated filter tipped cigarettes. On the other hand,the tipping paper must be securely fastened to the filter and tobaccocolumn. These lower and upper limits have been found to be about 0.5 cmand 5.0 cm respectively.

The combined or total porosity of the ventilated regions is also limitedby practical considerations. Too great a porosity will not permitsufficient resistance upon puffing and it will be difficult, if notimpossible, to smoke the cigarette. With too low a porosity, the resultsare similar to those obtained for small ventilated regions. Total orcombined porosities of about 1 cc/sec to about 10 cc/sec have been foundsuitable.

Although the pattern of ventilated areas in the filter is not criticalto the present invention, FIGS. 3(a), 3(b) and 3(c) depict variouspatterns of ventilated regions 30, 31, 32 formed by selectively applyingthe adhesive 33. FIGS. 3(a) and 3(b) respectively illustratelongitudinally and circumferentially disposed ventilated regions 30, 31.FIG. 3(c) is a combination of the patterns of FIGS. 3(a) and 3(b),providing discrete ventilated regions in a checkerboard appearance.Although FIGS. 3(a), 3(b) and 3(c) visually show the adhered regions, itis understood that this is for purposes of illustration only and that tothe eye there is no distinction between ventilated and non-ventilatedareas unless otherwise desired. It should also be noted that a singleventilated region may be employed when the critical relationshipsdescribed above are observed.

The mechanism by which the filter tipped cigarette of the presentinvention provides more constant performance between cigarettes is notcompletely understood. Although not to be construed as limiting, it isthought, however, that the small variations which result when utilizingthe ventilated cigarettes of the present invention are due in part tothe large area of the ventilated regions. Local imperfections in theventilated regions, being very small when compared to the area of theregions, do not substantially affect the performance of the ventilatedregions since the imperfections are statistically averaged out. Incontrast, imperfections in a band of perforations in the tippingenvelope more nearly approximate the area involved in ventilating and,consequently, have a much larger effect upon the total porosity of thetipping envelope.

in addition, as two layers of inherently-porous paper are employedacqording F the prefent Y the The ventilation index was calculated to be3.0 cm/sec chances of al/eragmg out limperfectlons mcrease( i' and 3.2cm/sec respectively. It should be noted that ff g i represegtatwe oftyplcal both average tar RSD and average pressure drop RSD aw ustratmg tl l s etw'een com/en in Table 2 are substantially less than any valuesshown tional ventilated filter tipped cigarettes and those made in Table1 showing a much more consistent product It i m accordance with the tishould be noted that the average tar RSD above 1s EXAMPLE 1 equal to orless than the average tar RSD for non-ventilated filter ti ci arettes,that value bein about 9%. Four dlfferfint brands of i m filter tlpPedThe ventilatior i ind ex of each prior art brar d, shown in qgaretteshaying perforated'tlppmg paper as ventlla' Example 1 is an order ofmagnitude greater than those tion mechanism were tested in accordancewith stand6 icted Table 2 1 dard procedures delineated by the FederalTrade Comp mission. Twenty-four cigarettes in groups of six from EXAMPLE3 grand S g corllsumed i i g i ccfof per Reference is made to Table 3 inwhich comprisons pu t roug t e co umn, eac pu emg 0 two sec- 1 ondsduration, at one minute intervals. The cigarettes are d of the yleld? ofSelected particulate i were consumed'to a 33 millimeter butt Table 1below and gas .phase constliuems between a convennona dc ictsllneasugements of each brand non-ventilated filter tipped clgarette andthose conp l 1 structed in accordance with the present invention. TestTable procedures identical to those used in Example 1 were Brand Venti-Average Average Average Average employed I i l 1 Table 3 Ventilated PuffTar Nicotine CO Pressure Area No. (mg). (mg) 8) Drop (mm (in) Control7.3 14.4 1.19 14 4.0 Porous Tipping 150 I p 8.2 9.6 0.86 10 3.0

T P P The tar, nicotine,'and carbon monoxide yields of the 22:; E igit;ifg ggi, 40 control cigarettes were substantially higher than the (1111ventilation porous tipped cigarettes of the present invention.

are) In summary, it may be seen that the porous filter A 2.5 13.1 1434.0 29 tipped cigarettes provide a means through which re 2 g; i3 2:;a? duced and consistent deliveries of total particulate mat- D 1:6 18:218 15.3 33 ter and gas phase constituents are obtained, thus fulfill-With the exception of brand C (70 mm) all other brands were 85 mmcigarettes. For comparison with other examples below, it should be notedthat the relative standard deviations (RSD) varied from 14% to 30% inaverage tar yield and 27% to 38% in average pressure drop of theventilation area. The ventilation index of brands A, B, C and D werecalculated to be 180 cm/sec. 110 cm/sec, 160 cm/sec and 370 cm/sec,respectively.

EXAMPLE 2 ing the objective as set forth hereinbefore.

The particular type of filter material employed is not a limiting factorsince the porous tipping as described and claimed herein may be employedwith cellulose acetate, activated carbon granules, and other materialsequally well. Although the descriptive matter generally describes thefilter as being unitary, this is also not to be construed as alimitation since multi-section filters function well in cooperation withporous tipping according to the present invention.

The term cigarette as used throughout the description and claims ismeant to include not only cigarettes but any tobacco product smoked inthe conventional sense such as, for example, a cigar or a cigarette witha filter tip attached thereto.

Having read and viewed the description and accompanying drawings,modifications, alterations, and variations will occur to those skilledin the art which do not depart from the scope of the invention asdefined in the appended claims.

What is claimed is: v

1. A ventilated filter tip cigarette comprising.

a. a tobacco column;

b. a filter enclosed by a porous, air permeable wrapper, characterizedby substantially uniform porosy;

c. an envelope characterized by substantially uniform porosity enclosingat least a portion of said enclosed filter, said envelope and wrapperbeing adhered together along at least one preselected region, but notover the entire area of their contiguous surfaces, the remainder of saidcontiguous surfaces being adhesive free, said envelope being airpermeable to permit ambient air flow through a sufficient area of theremainder of said envelope and wrapper so that said area provides aventilation index of from about 0.5 to cm/sec.

2. The filter tip cigarette of claim 1 in which the area of saidenvelope and wrapper which is air permeable to permit ambient air flowtherethrough is from about 0.5 to 5.0 cm

3. The filter tip cigarette of claim 1 wherein the ventilation index isfrom about 2.0 to 6.0 cm/sec.

4. A ventilated filter tip cigarette comprising:

a. a tobacco column;

b. a filter enclosed by a porous, air permeable wrapper characterized bysubstantially uniform porosy;

c. a porous envelope characterized by substantially uniform porosityenclosing at least a portion of said enclosed filter, at least onesurface of said envelope and wrapper being provided with an imperviouscoating along at least one preselected region, but not over the entirearea of said surface, to provide a portion of said area that is airpermeable to permit ambient air flow therethrough.

5. The ventilated filter tip cigarette of claim 4 in which a sufficientarea of the air permeable area permits the flow of ambient airtherethrough so that said area provides a ventilation index of fromabout 0.5 to 20 cm/sec.

6. The ventilated filter tip cigarette of claim 5 wherein theventilation index is from about 2.0 to 6.0 cm/sec.

7. The ventilated filter tip cigarette of claim 4 wherein the total areaof said remainder is from about 0.5 to 5.0 cm

8. An improved ventilated filter tip cigarette comprising:

a. a tobacco column:

b. a filter enclosed by a porous, air permeable wrapper characterized bysubstantially uniform porosity; and

c. porous, air permeable tipping paper characterized by substantiallyuniform porosity enclosing at least a portion of the enclosed filter, atleast one surface of said tipping paper or said wrapper being providedwith a substantially impervious coating so as to form at least oneregion which is coating-free to permit ambient air flow therethrough,wherein the area of the at least one said region is about 0.5 to 5.0 cmand the ventilation index is about 0.5, to 20 cm/sec.

9. The filter tip cigarette of claim 8 wherein the combined porosity ofsaid wrapper and said tipping paper is from about 1 to 10 cc/sec.

10. A ventilated filter tip cigarette comprising:

a. a tobacco column b. a filter enclosed by a porous, air permeablewrapper, characterized by substantially uniform porosy;

c. a porous envelope characterized by substantially uniform porosityenclosing at least a portion of said enclosed filter, said envelope andwrapper being adhered together along at least one preselected region,but not over the entire area of their contiguous surfaces, the remainderof said contiguous surfaces being adhesive free, at least a portion ofthe remainder being air permeable to permit ambient air flowtherethrough.

UNITED STATES PATENT OFFICE QERHFICATE OF CORRECTWN Patent No. 3, 924,643 Dated December 9 1975 Inventor) THOMAS WADE SUMMERS It is certifiedthat error appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

On the first page,

After the name of the assignee, insert:

Notice: The portion of the term of this patent subsequent to April 23,1991 has been disclaimed.

Signed and Sealed this first Day of June1976 {5mm Arrest:

RUTH c. MASON c. masmu. DANN Arresting Offirer Commissioner nfParems andTrademarks

1. A ventilated filter tip cigarette comprising: a. a tobacco column; b.a filter enclosed by a porous, air permeable wrapper, characterized bysubstantially uniform porosity; c. an envelope characterized bysubstantially uniform porosity enclosing at least a portion of saidenclosed filter, said envelope and wrapper being adhered together alongat least one preselected region, but not over the entire area of theircontiguous surfaces, the remainder of said contiguous surfaces beingadhesive free, said envelope being air permeable to permit ambient airflow through a sufficient area of the remainder of said envelope andwrapper so that said area provides a ventilation index of from about 0.5to 20 cm/sec.
 2. The filter tip cigarette of claim 1 in which the areaof said envelope and wrapper which is air permeable to permit ambientair flow therethrough is from about 0.5 to 5.0 cm2.
 3. The filter tipcigarette of claim 1 wherein the ventilation index is from about 2.0 to6.0 cm/sec.
 4. A ventilated filter tip cigarette comprising: a. atobacco column; b. a filter enclosed by a porous, air permeable wrappercharacterized by substantially uniform porosity; c. a porous envelopecharacterized by substantially uniform porosity enclosing at least aportion of said enclosed filter, at least one surface of said envelopeand wrapper being provided with an impervious coating along at least onepreselected region, but not over the entire area of said surface, toprovide a portion of said area that is air permeable to permit ambientair flow therethrough.
 5. The ventilated filter tip cigarette of claim 4in which a sufficient area of the air permeable area permits the flow ofambient air therethrough so that said area provides a ventilation indexof from about 0.5 to 20 cm/sec.
 6. The ventilated filter tip cigaretteof claim 5 wherein the ventilation index is from about 2.0 to 6.0cm/sec.
 7. The ventilated filter tip cigarette of claim 4 wherein thetotal area of said remainder is from about 0.5 to 5.0 cm2.
 8. Animproved ventilated filter tip cigarette comprising: a. a tobaccocolumn: b. a filter enclosed by a porous, air permeable wrappercharacterized by substantially uniform porosity; and c. porous, airpermeable tipping paper characterized by substantially uniform porosityenclosing at least a portion of the enclosed filter, at least onesurface of said tipping paper or said wrapper being provided with asubstantially impervious coating so as to form at least one region whichis coating-free to permit ambient air flow therethrough, wherein thearea of the at least one saiD region is about 0.5 to 5.0 cm2 and theventilation index is about 0.5 to 20 cm/sec.
 9. The filter tip cigaretteof claim 8 wherein the combined porosity of said wrapper and saidtipping paper is from about 1 to 10 cc/sec.
 10. A ventilated filter tipcigarette comprising: a. a tobacco column b. a filter enclosed by aporous, air permeable wrapper, characterized by substantially uniformporosity; c. a porous envelope characterized by substantially uniformporosity enclosing at least a portion of said enclosed filter, saidenvelope and wrapper being adhered together along at least onepreselected region, but not over the entire area of their contiguoussurfaces, the remainder of said contiguous surfaces being adhesive free,at least a portion of the remainder being air permeable to permitambient air flow therethrough.